Pope Leo IX, born Bruno of Egisheim-Dagsburg, was Pope from 12 February 1049 to his death in 1054. He was a German aristocrat and a powerful ruler of central Italy while holding the papacy. He is regarded as a saint by the Catholic Church, his feast day celebrated on 19 April.

On the death of Pope Damasus II in 1048, Bruno was selected as his successor by an assembly at Worms in December. Both the Emperor and the Roman delegates concurred. However, Bruno apparently favored a canonical election and stipulated as a condition of his acceptance that he should first proceed to Rome and be freely elected by the voice of the clergy and people of Rome. Setting out shortly after Christmas, he met with abbot Hugh of Cluny at Besançon, where he was joined by the young monk Hildebrand, who afterwards became Pope Gregory VII; arriving in pilgrim garb at Rome in the following February, he was received with much cordiality, and at his consecration assumed the name Leo IX.

Leo IX is widely considered the most historically significant German Pope of the Middle Ages.